Method of and apparatus for purifying sewage



J. R. DOWNES METHOD OF AND APPARATUS FOR PURIFYING SEWAGE Dec. 3, 1929.

Filed Sept. 22, 1928 5 Sheets-Sheet l YMMLW INVENTOR 7o/1n H. da

ATTO R N EYS Dec. 3, 1929. J. R. DowNEs 1,738,362

METHOD 0F AND APPARATUS FOR PURIFYING SEWAGE Y Filed Sept. 22. 1928 3 Sheets-Sheet 2 n f?. 00u/nes BY L3` I M 1 ATTORNEYS Dc. 3, 1929. J. R. DowNEs 1,733,362

- METHOD oF AND APPARATUS FOR PURIFYING sEwAGE Filed Sept. 22. 1928 5 Sheets-Sheet Fig 5.

g, q 'b/6a INVENTOR ATTORNEYS l Patented Dec. 3,-' 1929 lltl liti

UNITED STATES d'UHN B. DOWNES, OF MIDDLESEX, NEW JERSEY, 4ASSIG'lI'OIt TO PACIFIC FLUSH-.TANK

PATENT o Finca l COMPANYOF NEW YORK, N. Y., A CORPORATION OIE ILLINOIS METHOD F vAND .APPARATUS FOR .PRIFYING lSEWAGrIEl Application mea september e2, ieee.f serial No. 307,573.

rl"his invention relates to methods of Vand apparatus for urifying sewage. ln'the puri cation offsew'age by aeration, it is desirable to prevent the solids from settling and collecting on the bottom of the tank. Also, the air used for oxidizing and purifying the sewage should engage and contact with the entire mass thereof.

llt has been proposedto aerate or activate sewage by forcing air through porous plates at the bottom of the tank in which the sewage is contained. This method requires high pressure, due to the weight of the sewage mass and to the resistance oered by the porous plates. Furthermore, the plates become clogged by the solids that settle on the bottom of the tank and, therefore, require frequent cleaning. Moreover, the system just refer-red to necessitates the use of air cleaners and puriers to remove dust, oil and other impurities from 'theair utilized, since vsuch substances tend to clog the openings through the orous plates. 4 I 1 'this invention has for its salient object to provide ia simple, practical and efficient method of and apparatus for aerating or activating sewage. A'

Another object of the invention is to provide a method of'and apparatus for purifying sewage, so constructed and carried out and arranged that a minimum amount of apltd air cleaners and purifiers will not be required.'

Another object of the invention is to provide a method of and apparatus for maintaining the sewage in continuous motion during the aeration thereof.

Another object of the invention is to provide a method of and a paratus for aerati ing sewage, so arranged t at the introduction of air under pressure above the bottom of the tank will cause the sewage and sludge to be lifted thereby.

Another object of the invention is to proapparatus adapted for use in carrying out the f with method and constructed in accordance the invention; A Fig. 2 is a sectional elevation taken substantially on line 2-2 of Fig. 1;

Fig. 3 is a transverse sectional elevationy i taken substantially on line 3--3 of Fig. l;

Fig. 4' isa detail sectional elevation, partly broken away, taken substantially on line i- 4 of F ig. 2; and s f Fig is a detail sectional elevation show` ing a slightly modified form of discharge nozzle for one of the air inlet pipes.

The invention briefly 'described consists of a method of purifying sewage by aeration, which consists of forcing air into the lsewage and causing the sewage to be kept in motion during the aeration thereof. In carrying out the method, the sludge which settles by gravity on the bottom of the tank isprevented from accumulating by mechanical means, such as Scrapers, wtliich are moved back and forth or oscillated across the bottom of the tank. vFurthermore, the aeration is accomplished by introducing air into the sewagev abovethe bottom of the tank instead of `through perforated plates in the bottom of the tank. For instance, the air ma be introduced three feet below the leve ofthe sewage, and the apparatus is so arranged that the introduction of air in this manner will cause the sludge and sewage to be lifted through conduits, thus effecting an upward motion Yof the sewage at the side of the tank j char main portion of the ta where the aerating pipes are located. This motion of the sewage, in combination with the longitudinal motion of the sewage in the tank, due to the introduction' thereof at one end of the tank and dischar e of a portion thereof at the other end of t e tank, causes the sewage and sludge to travel through the tank from one Yend -to the other inb a spiral path.

Further details of the invention will appear from the following description.

In the form of apparatus illustrated, there .is shown an elongated tank 10, which may be formed of concrete or .other suitable material. An inlet trough 11 is provided for introducing the sewage into one end of the tank and a discharge trough 12 is formed at the top of the other end of the tank for 'conducting the aerated sewage or slud e from the tank. A

arcuate, as shown in Fig-.3, the rear portion f of the tank, viewing Fig. 1, being deeper than the 4front portion.

In order to prevent the solids from plugccumulating on the bottom of the hanical means is provide for scraping the sludge or solids from the bottom. This means consists of a plurality of plates or Scrapers 21, 22 and 23, carried y arms 24 mounted on a shaft 25 which in turn is 'carried b brackets 26 supported on the rear wall, e tank. Each of the Scrapers or plates is mounted on the lower end of two arms 24, and each set of arms has connected thereto legs 30 and 31 of a yoke 32. Each yoke 32 is oscillated by a link or pitman 33 whlch is connected at one end to the oke and at its oppJosite end toa disk 34. ach disk has secured 'thereto a gear 35 which meshes with a gear 36 carried by` a shaft 37, the shaft 37Jbeing driven from a shaft 38 by a worm and worm ggar connection 39 and 40. The shaft 38 may driven in any suitable manner.

From the fore oing description it will be clear that as the rive shaft 38 is rotated, the shaft37 will he drivenand through the gear connections and disk will cause the arms 24 and legs or Scrapers carried thereby to be oscillated back and'forth across the bottom of the tank. This movement ofthe Scrapers will prevent the bulking or accumulation of the sludge or so 'ds on the bottom .of the tank and will cause thismatter to be moved toward the bottoms of the lift pipes hereinafter de- The rear wall of the tank has formed on or secured thereto and projecting forwardly thereon, a shelf or ledge having its upper surface dis osed substantially at or slightly ow line or level of the sewage. The ledge 45'has secured thereto and projecting downwardly therethrough, a plurality of lift pipes 46 which are open at both ends. An air pressure conduit 50 is supported on the brackets 26 and has branchdischarge conduits 51 connected thereto, one discharge conduit extending downwardly into each of the lift pipes 46. v

The lift pipes at the right hand end of the tank, viewing Figs., 1 and 2,4are preferably made smaller in cross section and are designated by reference character 52. These pipes are open at their lower ends and the bottom of the tank is provided with a lurality of recesses or notches 53 disposed beneath the lower open ends of the pipes 52.

The upper ends of the pipes 52 communicate with angularl disposed conduits 55 which discharge at t eir other ends into a conduit 56 formed on the rear end portion of the end wall 27. The conduit 56 extends longitudinally of the tank throughout the length of the tank, one end communicating through passages 57 and 58 with the intake trough l1. The conduit 56 also communicates intermediate its ends with a discharge conduit 59 through which the material is conducted away from the'tank to sewage digestion tanks or other desired apparatus.

In the apparatus above described, the method operates as follows: From the showing, particularly in Fig. 1, it will be seen that the sewage low's into the tank at one end. The solids tend to settle in the tank to the bottom thereof and as they settle they collide with other portions of the material which adhere thereto. The sludge or solid matter, however, is prevented from accumulating or bulking on the bottom of the tank by the oscillating plates or Scrapers which scrape the material downwardly to a position adjacent the lower ends of the air liftpipes 46. Air is forced under pressure through the conduits 51 and engages the sludge, solids and the liquid matter, thus making this matter more buoyant than the remaining mass of sewage. Since the portion of the material aerated by the air is more buoyant, the weightof the remailling mass of sewage will force this material in which the air is entrained upwardly in the air lift pipes 46 and the aerated material will be discharged from the pipes 46 onto the shelf or ledge 45 which, as above stated, is

located at or near the flow line of the sewage. The sewage becomes further aerated las it is discharged on or splashes on the shelf or ledge 45. The material so discharged is caused to'low across the surface of the tank contents and turns downwardly again toward the bottom of the tank and back to the intake I settle tend to accumulate larger 'aggregates of material.) These aggregates, due to the aeration described, will entrain and absorb enough air from the air lift to keep them, from becoming septic for a short time, and the Scrapers, as stated, forward them again to the intake ends of the air lift pipes before the entrained air is exhausted. The aerating process is then repeated..

llt will be obvious that a portionfof the air l' used to aerate the material and to lift the liquid and solids in suspension in the air lift pipes willI escape into the atmosphere, but the portion absorbed by or entrained by the liquid and solids will continue'its purication work since the oxygen in ,the air serves to stabilize the organic matter of the sewage -f and particularly in conjunction with the loc- Y culent solids, oxidation will take place so dll rapidly that no disagreeable odor will escape into the atmosphere from the sewage.

rllhe portion of the tank in which the lift pipes 52 are located is used forfsedimentation and, therefore, undue agitation is avoided therein. The lift pipes 52 donot deliver the material to the ledge but the sludge which settles in this portion of the tank is partially returned through the conduit 56 to the intake end of the tank and is also partially discharged from the` apparatus through the conduit 59. Any excess of sludge or solid 'matter over that required to maintain' the process in operation is removed as required through the conduit 59 or othpr vconduits leading to sewage digestion tanks or other desired aptill fdd

titl

parat'us.

lf desired, the lower ends of the air discharge conduits 5l may be flared as shown in llig'. 5, and a plug 60 may be supported in the air litt pipe t6 or 52 beneath the discharge end of the conduit 5l. The plug, as shown 1n lfig. 5, tends to deflect the air laterally and tacilitate the upward movement of the material in the lift pipe. The shape of the lower portion of the plug deilects the sludge laterally awayfrom the lower end of the conduit 5l and toward the upward current.

lllrom the foregoing description it will be seen that the/method and apparatus outlined will cause the sewa e to move in a spiral path from one en d of t e tank to the other, In this way the solid matter will be repeatedly aerated or acted upon by Nthe air. Furthermore, the scillating movement of the scrapers will preven any undue accumulation or bulking of theilsolids on the bottom of the tank.

Since the/lair lwhich is used for aerating and vly through the p' lifting the material is introduced into the tank in the upper portion of the sewage, it

will be obvious that very much less pressure,

of air is required than is required in an apparatus in which the air is introduced through porous plates in the bottom of theV tank.

It should be clear from the above explanation that the method and a paratus described is simple, practical ande cient, and is capa- Ible of continuous use without requiring any cleaning of the parts or any air cleaner or strainer.

Although certain forms of apparatus have been particularly shown `and described, it will be clear that the method can beA carried out by other apparatus and that changesin the construction and in the arrangement of the various parts of the apparatus may be made without vdeparting from the spirit or scope Aof the invention, as expressed in the following claims.

What I claim is:

1. Apparatus for purifying sewage comprising a tank, air inlet pipes arranged adjacent one wall of the tank, and means for scraping material across the bottom of the tank toward said wall.

2. Apparatus for purifying-sewage comprising a tank, air lift pipes inthe tank, and means for discharging air into said the upper portions thereof.

3. Apparatus for purifying sewage comprising a tank, a ledge in said tank havlng an upper surface located near the level of the sewage in the tank, lift pipes mounted on and extending downward through the ledge, and means for causing the sewage to tlow upward- 1 es. 4. Apparatus fldr purifying `sewage comprising atank, a ledge in said'tank having an upper surface located near the level of -the sewage in the tank, lift pipes mounted on and extending downward through the ledge, and means tor causing the sewage to low upwardly through the pipes, the upper ends of the pipes being open and disposed adjacent the upper surface of the ledge.

pipes inv 5. Apparatus for purifying sewage coml prising a tank, means for conducting sewage into the tank at one end, a dlscharge conduit adjacent thelother end of the tank, and means adjacentpne wall of the tank for raising and aerating sewage in the tank.

6. Apparatus for purifying sewage comprising a tank, air inlet pipes arranged adjacent one wall of the tank, and oscillatingvv means for scraping material across the bottom4 of the tank toward said wall.

JOHN R. DOWNES.

iai 

